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Biomedical subjects

R Stefani

Publications and source records attributed to R Stefani.

At least 19 recordsLinked to original sources
PubMed2001

LC coupled to ion-trap MS for the rapid screening and detection of polyphenol antioxidants from Helichrysum stoechas.

Liquid Chromatography-Ion Trap Mass Spectrometry with an atmospheric pressure chemical ionization (APCI) interface in the negative and positive-ion modes in parallel to UV-diode-array detection (DAD), was applied for the rapid detection/characterization in crude extracts of the water-soluble antioxidant phenolics from Helichrysum stoechas. APCI-MS provides unequivocal molecular weight data of these compounds and useful information about their structures (diagnostic fragments ions), which were confirmed by the UV-DAD fingerprints. This combined approach allows the identification of ten constituents, including the three naturally occurring isomers of caffeoylquinic acid (CGAs), namely neo-chlorogenic acid, chlorogenic acid and crypto-chlorogenic acid, 2 isomeric dicaffeoyl quinic acids, 2 isomeric naringenin glucosides, quercetin, kaempferol and apigenin glucosides and a tetrahydroxychalcone-glucoside. The water-soluble extract from H. stoechas, standardized in both total polyphenol and kaempferol-3-glucoside content, exhibits strong antioxidant activity in vitro when tested in both artificial membrane systems (phosphatidylcholine liposomes) and in a cell model (rat erythrocytes).

Animals↗
PubMed1999

[A case of intestinal obstruction after migration of esophageal endoprosthesis].

Endoscopic dilatation and stenting are the procedures of choice in the treatment of oesophago-gastric anastomotic stricture following oesophagectomy, leading to immediate relief of dysphagia with a low procedure-related risk. Prosthesis displacement is a described late complication, easy detected and sorted out whenever possible with endoscopic retrieval. A case in which stent migration ended at the terminal part of the small intestine, presenting with the clinical features of mechanical ileum, is described.

Aged↗
PubMed1998

Mass spectrometric characterization and HPLC determination of the main urinary metabolites of nimesulide in man.

A study was undertaken for the characterization and quantitative determination of the main urinary metabolites of the non-steroidal anti-inflammatory drug (NSAID) nimesulide (4-nitro-2-phenoxy-methanesulfonanilide) in man following single oral administration (200 mg). Urines were collected from six healthy volunteers at 12, 24, 48, 72 and 96 h post-administration and submitted to liquid liquid extraction before (free metabolites) and after enzymatic hydrolysis (conjugated metabolites). The structure of the metabolites, isolated by TLC separation, was elucidated by mass spectrometry (electron impact ionization) and confirmed by synthesis. Five metabolites were identified: they arise from hydroxylation to the phenoxy nucleus (M1 = hydroxynimesulide); reduction of the nitro group to an amino derivative (M2); concomitant hydroxylation and reduction (M3); N-acetylation of the M2 (M4) and of the M3 (M5) metabolites. Quantitation was by reverse phase high performance liquid chromatography (Supelcosil LC-18 DB column; mobile phase: sodium phosphate buffer (pH 3.0, 50 mM)-acetonitrile (gradient elution); flow rate: 1 ml min(-1); UV detection, 230 nm), procedure which allows in a single chromatographic run the simultaneous determination of the unchanged drug and of its metabolites. The urinary excretion of the drug and metabolites (free + conjugated) in the overall 96 h-interval accounts for approximately 40% of the administered dose: 17.55 +/- 3.6% M1; 0.72 +/- 0.43% M2; 2.45 +/- 1.22% M3; 19.07 +/- 4.3% M5. The bulk of the metabolites was in conjugated form. Percentages excretion of the unchanged drug and of M4 metabolite were below 0.5%. The described method is suited to specifically and quantitatively measure nimesulide and metabolites in human urine with acceptable precision and accuracy.

Adult↗
PubMed1995

Anti-elastase and anti-hyaluronidase activities of saponins and sapogenins from Hedera helix, Aesculus hippocastanum, and Ruscus aculeatus: factors contributing to their efficacy in the treatment of venous insufficiency.

Triterpene and steroid saponins and sapogenins of medicinal plants (Aesculus hippocastanum L., Hedera helix L., Ruscus aculeatus L.) are claimed to be effective for the treatment/prevention of venous insufficiency. In this work we evaluated the inhibitory effects of these plant constituents on the activity of elastase and hyaluronidase, the enzyme systems involved in the turnover of the main components of the perivascular amorphous substance. The results evidence that for Hedera helix L., the sapogenins only non-competitively inhibit hyaluronidase activity in a dose-dependent fashion, showing comparable IC50 values (hederagenin IC50 = 280.4 microM; oleanolic acid IC50 = 300.2 microM); both the saponins hederacoside C and alpha-hederin are very weak inhibitors. The same behaviour is observed for serine protease porcine pancreatic elastase: the glycosides are devoid of inhibitory action, while genins are potent competitive inhibitors (oleanolic acid IC50 = 5.1 microM; hederagenin IC50 = 40.6 microM). Constituents from Aesculus hippocastanum L. show inhibitory effects only on hyaluronidase, and this activity is mainly linked to the saponin escin (IC50 = 149.9 microM), less to its genin escinol (IC50 = 1.65 mM). By contrast, ruscogenins from Ruscus aculeatus L., ineffective on hyaluronidase activity, exhibit remarkable anti-elastase activity (IC50 = 119.9 microM; competitive inhibition). The mechanism of elastase inhibition by triterpene and steroid aglycones, with a nitroanilide derivative as substrate, is discussed.

Animals↗
PubMed1994

[The conservative treatment of infected vascular prostheses in surgery to revascularize the lower limbs].

Infected vascular grafts are associated with very high rates of limb loss and mortality. "Classic" treatment has invariably included graft excision. Recent reports have suggested that a more conservative approach may be indicated in selected cases, leaving the graft in place and using an aggressive local treatment associated with appropriate intravenous antibiotics. The authors report their experience with two patients with infected prosthetic vascular grafts in the groin. They both had purulent drainage from the groin wound, with the graft exposed close to the femoral anastomosis. They were both treated successfully without graft removal, and both graft maintained patency, with a follow-up of 22 and 19 months.

Aged↗
PubMed1994

[Pulmonary carcinosarcoma].

Sarcomatoid carcinomas of the lung are uncommon neoplasms; the concurrent presence of malignant epithelial and sarcomatoid spindle cell components show a high malignancy. Lymph node metastases at presentation is an important prognostic factor, on the other way the most patients with sarcomatoid carcinoma of the lung usually presented at an advanced stage that needed a complementary therapy. The Authors report about one surgical case of pulmonary carcinosarcoma recently observed without lymph node metastases; the literature is reviewed and the histogenesis is discussed.

Carcinosarcoma↗
PubMed1993

[Rectal foreign bodies. Principles of therapy].

The authors report their experience with the treatment of endorectal foreign bodies (EFB). They review the literature on the subject and examine the various therapeutic options. Considering the possible complications of leaving an EFG in place for prolonged period of times in the hope of spontaneous delivery, they suggest that immediate removal is always indicated. They describe various technical modalities for endoscopic removal, that can avoid laparotomy in the majority of cases.

Adult↗
PubMed1993

[Subacute Budd-Chiari syndrome treated with rTPA. Considerations on a case].

The authors report on a case of hepatic vein thrombosis or Budd-Chiari syndrome (BCS) successfully treated with recombinant Tissue Plasminogen Activator (rTPA). They briefly outline the etiology and symptomatology of this disease as well as the various surgical procedures used for treatment. Medical therapy has been so far poorly effective in treatment BCS, but recently various reports seem to indicate that rTPA may have a role. The authors suggest that rTPA may be used as the only therapy in selected cases, or in treating patients that are not candidates for surgical intervention, or as a temporizing measure to improve symptoms in patients awaiting surgery.

Acute Disease↗
PubMed1993

[Calculosis of the cystic duct].

The authors report on three cases of cystic duct syndrome, a fairly uncommon complication of cholelithiasis, consisting in migration of a large gallstone from the gallbladder to the common bile duct, resulting in the formation of a common cavity between cystic, hepatic and common bile ducts. They review the pathogenesis of this entity, as well as the diagnostic modalities best suited to a precise diagnosis. They stress that surgical therapy must be chosen on a case by case basis, trying to restore a functional extrahepatic biliary tree.

Aged↗
PubMed1993

[Caroli's disease associated with cholangiocarcinoma. A case of our own observation].

The authors report a case of Caroli's disease associated with cholangiocarcinoma. The patient presented with pain and jaundice and ultrasonography disclosed multiple common bile duct stones, cystic dilatation of the extrahepatic biliary tree and a mass in the right lobe of the liver. At operation, after a frozen section demonstrated cholangiocarcinoma, a common bile duct exploration, right hepatic lobectomy and hepato-jejunostomy were performed. They review the literature on the subject and stress the fact that hepatic tumors are associated with Caroli's disease in 7% of cases. Therefore, in these patients, when a stenosis of the biliary tree is found, multiple diagnostic manoeuvres are indicated in order to exclude the presence of malignancy.

Aged↗
PubMed1993

[The Knight-Griffen technique in colorectal surgery].

The use of stapling devices has changed the practice of colorectal surgery. The authors report their experience with the "double stapling" technique introduced by Knight and Griffen in 1980 for the performance of low colorectal anastomosis. They treated 42 patients, with a mean age of 63.2 years. In 34 surgery was performed for rectal adenocarcinoma, while 8 patients were being reoperated on for closure of a colostomy after Hartmann's operation. In one patient a diverting colostomy was fashioned because of poor bowel cleansing, secondary to a stenosing rectal carcinoma. Mortality was nil. There were no clinical anastomotic leaks. There were 2 cases of late postoperative anastomotic stenosis that responded to endoscopic pneumatic dilatation.

Adenocarcinoma↗
PubMed1993

[Inguinal hernia surgery under local anesthesia. Technical note and immediate results].

The authors report their experience on local anesthesia for inguinal hernia repair in 164 patients. They describe the neuroanatomy of the inguinal region as well as the technique of loco-regional anesthesia. The Shouldice repair was most frequently employed, followed by the Bassini repair. Local anesthesia was very well tolerated by the patients, sometimes with the addition of mild sedation. The postoperative course was definitely shortened by the use of local anesthesia, and all patients were able to take a regular diet and to walk few hours after surgery.

Aged↗
PubMed1993

[Surgical treatment of toxic megacolon].

After an introduction on the various aetiological factors involved in toxic megacolon, its onset, medical treatment and indications to surgery, the paper describes personal experience with seven cases. The report highlights the importance of medical treatment which is recommended as the appropriate initial therapeutic approach. Then after a review of evolving surgical techniques, it is suggested , again on the basis of personal experience, that the surgical approach should be neither excessively aggressive (total proctocolectomy with permanent ileostomy) nor excessively conservative (multistoma decompression). According to this report, the operation of choice is currently subtotal colectomy plus ileostomy and sigmoidostomy which combine modest morbidity and mortality with the possibility of future reconstruction.

Adult↗
PubMed1993

[Acute intestinal infarction. Diagnostic and therapeutic problems].

The authors report their experience in thirteen cases of mesenteric infarction. They emphasize the difficulty in diagnosing and treating this entity, considering also the impossibility in most centers of performing emergency selective angiography of the superior mesenteric artery (SMA) When feasible, mesenteric rivascularization should always be attempted, followed 24 hours later by a "second look" procedure.

Acute Disease↗
PubMed1993

[Modified radical mastectomy in local anesthesia].

The authors report their experience on the use of local anesthesia for modified radical mastectomy. They have used this modality in five patients who could not undergo general anesthesia because of underlying severe medical illness and in a sixth one who adamantly refused general anesthesia. They describe in detail the technique used, stressing the importance of a thorough knowledge of regional neuroanatomy. There were no complications in their small series. The authors conclude by stating that the use of local anesthesia may expand the indications for "toilet mastectomy" to include patients in poor medical condition, unsuitable for general anesthesia.

Aged↗